Person: OKTAR, FAİK NÜZHET
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OKTAR
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FAİK NÜZHET
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Publication Metadata only Sintering effect on mechanical properties of composites of bovine hydroxyapatite (BHA) and Li2O(Trans Tech Publications Ltd, 2006) OKTAR, FAİK NÜZHET; Oktar F.N., Demirer M.R., Gunduz O., Genc Y., Agathopoulos S., Peker I., Ozyegin L.S., Salman S.In this study, hydroxyapatite (HA) material, obtained from calcinated bovine bone (BHA), was mixed with 0.25, 0.50, 1.00, and 2.00 wt% Li 2CO3. The pressed pellets were sintered at various sintering temperatures between 900°C and 1300°C. Measurements of compression strength, microhardness, and density, along with SEM observation and X-ray diffraction analysis were performed. The experimental results showed that the samples with 0.25 and 0.50% Li2CO3. reached a maximum of densification and the highest values of compression strength and microhardness were achieved after sintering at 1300°C. The wetting effect of a Li2O-associated glassy phase was observed even from 900°C.Publication Open Access Fabrication of naturel pumice/hydroxyapatite composite for biomedical engineering(BMC, 2016-12) OKTAR, FAİK NÜZHET; Komur, Baran; Lohse, Tim; Can, Hatice Merve; Khalilova, Gulnar; Gecimli, Zeynep Nur; Aydogdu, Mehmet Onur; Kalkandelen, Cevriye; Stan, George E.; Sahin, Yesim Muge; Sengil, Ahmed Zeki; Suleymanoglu, Mediha; Kuruca, Serap Erdem; Oktar, Faik Nuzhet; Salman, Serdar; Ekren, Nazmi; Ficai, Anton; Gunduz, OguzhanBackground: We evaluated the Bovine hydroxyapatite (BHA) structure. BHA powder was admixed with 5 and 10 wt% natural pumice (NP). Compression strength, Vickers micro hardness, Fourier transform infrared spectroscopy, scanning electron microscopy (SEM) and X-ray diffraction studies were performed on the final NP-BHA composite products. The cells proliferation was investigated by MTT assay and SEM. Furthermore, the antimicrobial activity of NP-BHA samples was interrogated. Results: Variances in the sintering temperature (for 5 wt% NP composites) between 1000 and 1300 degrees C, reveal about 700 % increase in the microhardness (similar to 100 and 775 HV, respectively). Composites prepared at 1300 degrees C demonstrate the greatest compression strength with comparable result for 5 wt% NP content (87 MPa), which are significantly better than those for 10 wt% and those that do not include any NP (below 60 MPa, respectively). Conclusion: The results suggested the optimal parameters for the preparation of NP-BHA composites with increased mechanical properties and biocompatibility. Changes in micro-hardness and compression strength can be tailored by the tuning the NP concentration and sintering temperature. NP-BHA composites have demonstrated a remarkable potential for biomedical engineering applications such as bone graft and implant.Publication Metadata only Sintering effect on mechanical properties of composites of enamel derived hydroxyapatite (EHA) and titanium(Trans Tech Publications Ltd, 2006-05-15) OKTAR, FAİK NÜZHET; Gunduz O., Oktar F.N., Oz B., Altundal H., Agathopoulos S., Salman S., Ovecoglu L.Hydroxyapatite (HA) is one of the most promising biomaterials, which is on use since decades in biomedicine. Because of the known mechanical weakness of HA in load carrying situations, various dopants, like ceramic oxides and metallic particles, have been used to produce HA-composite materials. In this study, Ti powders were admixed with enamel derived HA at 5 and 10 wt %. After ball milling, the mixtures were uniaxially pressed into pellets of a cylindrical form. The composites were sintered at temperatures between 1000°C and 1300°C. Microhardness, compression strength, and density measurements together with X-ray diffraction analysis and SEM studies were performed. The best mechanical values were obtained for the samples sintered between 1100°C and 1300°C.Publication Metadata only Sintering effect on mechanical properties of composites of bovine derived hydroxyapatite (BHA) with titanium(Trans Tech Publications Ltd, 2006) OKTAR, FAİK NÜZHET; Ozyegin L.S., Gunduz O., Oktar F.N., Oz B., Agathopoulos S., Salman S., Ovecoglu L.The aim of this study was to prepare high performance biomaterials suitable for use at load bearing applications with high bioactivity. The hydroxyapatite (HA) was prepared from bovine bones via calcination technique. The bovine derived HA (BHA) was mixed with 5 and 10 wt% metallic titanium (Ti) and the obtained homogenous mixtures were pressed to produce the test samples. The compacts were sintered at temperatures between 1000 and 1300°C. Compression strength, density, and microhardness were measured. SEM and X-ray diffraction studies were also made. The best mechanical properties were obtained between after sintering at 1200-1300°C.Publication Metadata only Composites of bovine hydroxyapatite (BHA) and ZnO(SPRINGER, 2008) OKTAR, FAİK NÜZHET; Gunduz, Oguzhan; Erkan, Eray M.; Daglilar, Sibel; Salman, Serdar; Agathopoulos, Simeon; Oktar, Faik NuzhetComposites of calcinated bovine bone-derived hydroxyapatite (BHA), doped with 2.5, 5, and 10 wt.% ZnO were produced by sintering. Scanning electron microscopy (SEM) and X-ray diffraction analysis together with measurements of density, compressive strength, and Vickers microhardness were carried out in the sintered samples. The experimental results showed that the best mechanical properties were achieved in the samples with 5% addition of ZnO. The highest value of compression strength was achieved after sintering at 1200 degrees C (72 MPa) and of microhardness at 1300 degrees C (548 HV). Prolong heat treatment at 1300 degrees C results in vulnerable BHA-ZnO composites to over-firing effect.